Figure 1.

Experimental procedure. Mothers-to-be (n = 34; fetus < GA34) taped two different nursery rhymes during a visit in our laboratory and were afterwards assigned (randomly) to two groups. In the experimental group (EG, n = 22), one nursery rhyme was replayed to the fetus (80 dB over loudspeakers; presented twice daily for five minutes) the last six weeks (>GA34) until birth. In the control group (CG, n = 12), fetuses were not stimulated with any rhyme. After birth (two and again five weeks) EG and CG infants’ electrocardiography (ECG) and high-density electroencephalography (hdEEG) were collected during auditory stimulation with both rhymes presented with both voices, namely the familiar (maternal) and an unfamiliar female voice. GA = gestational age.